Add github actions.

Author: kszymukowicz

.github/workflows/ci.yml

@@ -0,0 +1,68 @@
+name: CI
+
+on: [ push, pull_request ]
+
+jobs:
+  build:
+    runs-on: ubuntu-18.04
+
+    continue-on-error: ${{ matrix.env.experimental == true }}
+    strategy:
+      fail-fast: false
+      matrix:
+        env:
+          - { php: 7.4, TYPO3_VERSION: ^10.4, TESTING_FRAMEWORK: ^6.5.0 }
+          - { php: 7.3, TYPO3_VERSION: ^10.4, TESTING_FRAMEWORK: ^6.5.0 }
+          - { php: 7.4, TYPO3_VERSION: ^11.0, TESTING_FRAMEWORK: ^6.6 }
+          - { php: 8.0, TYPO3_VERSION: ^11.0, TESTING_FRAMEWORK: ^6.6 }
+
+    env: ${{ matrix.env }}
+
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.env.php }}
+          tools: composer
+          extensions: pdo, sqlite3
+
+      # composer
+      - name: Update Composer
+        run: |
+          sudo composer self-update
+          composer --version
+      - name: Validate composer.json and composer.lock
+        run: composer validate
+      - name: Cache dependencies
+        uses: actions/cache@v1
+        with:
+          path: ~/.composer/cache
+          key: dependencies-composer-${{ hashFiles('composer.json') }}
+
+      - name: Ensure stability dev
+        if: ${{ matrix.env.TYPO3_VERSION == 'dev-main' }}
+        run: |
+          composer config minimum-stability dev
+          composer config prefer-stable true
+      - name: Install TYPO3 core
+        run: composer require typo3/cms-core="${TYPO3_VERSION}" ${PREFER_LOWEST};
+
+      - name: Install testing framework ${{ matrix.env.TESTING_FRAMEWORK }}
+        if: ${{ matrix.env.TESTING_FRAMEWORK }}
+        run: composer require --dev typo3/testing-framework="${TESTING_FRAMEWORK}";
+
+      - name: Install prophecy trait
+        if: ${{ matrix.env.TESTING_FRAMEWORK }}
+        run: composer require --dev phpspec/prophecy-phpunit="^2.0";
+
+        # unit tests
+      - name: Unit Tests
+        run: |
+          echo "Running ${TYPO3_VERSION} unit tests with $(which php)";
+          .Build/bin/phpunit -c .Build/vendor/typo3/testing-framework/Resources/Core/Build/UnitTests.xml Tests/Unit/;
+
+      - name: Reset composer.json
+        run: git checkout composer.json;